1. Field of the Invention
The present invention relates to a power supply unit used for a hybrid vehicle or an electric vehicle.
2. Description of the Related Art
For example, in an electric vehicle driving with an electric motor, or a hybrid vehicle moving with an engine and the electric motor, a power supply unit 200 (for example, see Patent Document 1) as shown in FIG. 13 is mounted as a driving source of the electric motor.
The power supply unit 200 shown in FIG. 13 includes: a plurality of batteries 202 each having a positive electrode 203 at one side and a negative electrode 204 at the other side; and a pair of end plates 205 (only one of the end plates is shown) clamping the batteries 202 therebetween; and a bus bar module 210 connecting the batteries 202 in series.
The batteries 202 are arranged in a line so that the positive electrode 203 and the negative electrode 204 of the batteries adjacent to each other are adjacent to each other. Further, each of the electrodes 203, 204 is formed in a male screw shape for allowing a nut 217 shown in FIG. 13 to be screwed therewith.
The bus bar module 210 includes: a plurality of bus bars each electrically connecting the positive electrode 203 and the negative electrode 204 of the batteries adjacent to each other; a plurality of nuts fixing the bus bars 216 with the electrodes 203, 204; and a plate 211 made of synthetic resin for positioning the bus bars 216 in predetermined positions. Further, the bus bar 216 is made of a flat metal plate having a pair of through holes. The positive electrode 203 and the negative electrode 204 of the batteries adjacent to each other are inserted into the pair of through holes.
When assembling the power supply unit 200, firstly, the batteries 202 are arranged in a line, then, the pair of end plates 205 clamps the batteries, and a not-shown band or the like fixes the batteries 202 with the pair of end plates. Then, the plate 211 and the bus bars 216 are overlapped with the electrodes 203, 204 of the batteries 202. In this case, the electrodes 203, 204 are respectively inserted into the pair of through holes of the bus bar 216. Then, the nuts 217 are screwed with the electrodes 203, 204 penetrating the through holes to fix the bus bar 216 to the electrodes 203, 204. Namely, the bus bar 216 is electrically connected to the electrodes 203, 204. Thus, the power supply unit 200 is assembled.
[Patent Document 1] Japanese Published Patent Application No. 2004-31049
However, in the conventional power supply unit 200, the bus bar 216 is fixed to the electrodes 203, 204 by screwing the nuts 217 with the electrodes 203, 204 penetrating the through holes of the bus bar 216. Therefore, there is a problem that the number of screwing positions of the nuts 207 and the electrodes 203, 204 is large, and an assembling man-hour is increased.
Accordingly, an object of the present invention is to provide a power supply unit which can be assembled with a reduced assembling man-hour.